This invention was made in the course of, or under, a contract with the United States Department of Energy.
Large superconducting magnets are beginning to be used in such fields as nuclear physics, large-scale energy storage, and controlled thermonuclear fusion research. Many parameters, such as operating current, stored energy, and cryostatic stability (to name only a few), influence the various magnet designs.
In applications such as the poloidal field system and the toroidal field coils of superconducting tokamaks, magnets are required that must withstand large pulsed magnetic fields. Magnets that are wound in the pancake configuration are generally preferred for these applications because of their superior mechanical properties. However, since splices between the pancakes have always been required, the layer-wound types have most often been chosen. Since the layer-wound coils have a disadvantage in supporting magnetic forces, catastrophic failures are still occasionally experienced with these magnets.
Furthermore, in any coil whether superconducting or normal room temperature, it is beneficial to keep splices to a minimum. Splices often have contact resistance, reduced strength in tension, increased cooling problems, and consume time and labor in their fabrication. Therefore, the need exists for a method of winding multiple pancake coils from a continuous superconductor cable. The present invention was conceived to meet this need in a manner to be described hereinbelow.